Question about 1994 Nissan 240SX

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HIGH NO ppm READINGS - 1994 Nissan 240SX

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It could be a number of things, but usually, a lean fuel mixture is the culprit. Try replacing all filters and running a fuel system cleaner for a few tanks (i like Lucas Oil's products). It can also be caused by advanced ignition timing. Also, make sure your EGR is working properly, as this too is a likely culprit.

Hope this helps,

Posted on Oct 06, 2009

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I have a 1989 ford f-150 4.9l straight 6 that has failed emission for high idle. in New Jersey testing the standard is 220 hc ppm. The readings has been as high as 5182. I've cleaned and changed the...

seems like those may be two different issues. check for vacuum leaks and have your fuel psi checked. High fuel pressure can change your emissions numbers. I believe the fuel psi should be 30-45 psi. if its way above that then the nest step is to check the fuel pressure regulator

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fist i would like you to post the year make and model of the truck along with the HC ppms and NOX ppm it would be very helpful but high hc and nox can be attributed to a faulty EGR system nox is produced when the combustion chamber temperature gets too high so a small amount of exhaust is cycled back into the air stream to help cool them there are other causes but without looking at the levels its much harder to say

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High CO and HC 1992 Toyota Camry

hi i have a toyota camry 1992 and it didn't pass emissions its reading 1048 no ppm rpm and it will allow 910

Apr 01, 2012 | Toyota Camry Cars & Trucks

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What should i do to pass hydrocarbons inspection

you don`t say if this reading is at idle or during the drive portion of the e-test.hydrocarbons is unburnt fuel which could be even an over rich condition such as too much fuel through the injectors or a bad tps switch,map/af sensor,the car could be running too cool indicating it needs more don`t say what the other gas readings where during the test as this can help find the problem even if they fall within acceptable might want to have this checked out at a shop that knows how to diagnoise emmission problems.

Feb 09, 2012 | 1993 Buick LeSabre

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What makes my HC and No (PPM) read so high on my emissions test

there are any number of things that could cause this, most of which need a computer diagnostic test to find and remedy.

the most common cause is also the simplest and cheapest to fix.
a dirty air filter will cause HC and NO readings to be high.
change the air filter, even if it looks clean. it is a cheap part and easy to install.
unless you have changed the filter in the last couple of months, do this first and take the car on a 40-50 mile run to clear the engine. then have the emissions checked again.

if this doesn't work then you will probably need a computer diagnostic test to identify the problem area.

hope this helps

Apr 28, 2011 | Toyota Camry Cars & Trucks

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An old worn out engine will have high emmisions due to burning oil. Also, with age, a catalitic converter won't burn up any fuel vapors causing high emmisions.

Sep 11, 2010 | Isuzu Rodeo Cars & Trucks

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1996 cavalier failed e-test with high readings on No PPM. limit is 526, reading was 1953...where do i start for repairs to re-test..

Depending on the engine , if it is running diesel , put a couple of litres of cooking oil in tank the when it is low and run the car for a few miles.

Take it in while it is running on that mix and the emissions will drop to virtually nil.

If it is petrol it may need a proper service and tune up or the catalyser in the exhaust may be shot

Sep 16, 2009 | 1996 Chevrolet Cavalier

1 Answer

What will bring readings into limit

A failing oxygen (O2) -sensor will give failing emission tests. Normally you also get other symptoms:

- too high fuel consumtion
- bad acceleration, stalling problems, sputtering
- the check engine light comes on indicating that the engine control unit has recorded error codes (which will be related to readings of incorrect fuel/air ratio when read by the OBD diagnostics tool at a repair shop).

It is always a good idea to see if you can get any readings from the check engine light if present or much better by an OBD reader to be as certain as possible.

Another component that could cause failing emissions tests is the catalytic converter, giving a similar range of symptoms. To determine if this is the cause is not so easy on older cars with only one O2 sensor, it requires diagnostic skills and equipment. On newer cars with OBDII-systems it will give a recognizable fault code for the cat converter.

Then there are also the issues of the actual cause of malfunction in either or both of these components, is it due to old age and normal wear and tear or is it due to contamination from burning oil (blue tail pipe smoke) or anti-freeze (white smoke), misfiring, etc? Then the cause must be treated as well for a successful repair.

Normally these components have a very long life span and should not have to be replaced more than once or maybe twice for the sensors during the car's lifetime in an otherwise health engine.

Good luck!

May 25, 2009 | 1992 Honda Accord

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My 1992 Cutlass Supreme SL Olds failed emissions.

High NOX readings indicate a somewhat lean condition IE: hot exhaust. Possible causes are cracked and leaking vacuum lines or lazy oxygen sensors. If possible have a reputable garage with engine electronics scanner services check the sensor to see if its helping to create the lean condition

Apr 25, 2009 | 1992 Oldsmobile Cutlass Supreme

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